Let's analyze the given covalent molecules to determine which one does not have the proper Lewis formula.
1. H-C-O-H (Methanol)
2. H-O-H (Water)
3. H-S-S-H (Disulfane)
4. H-B-B-H
We'll assess these structures based on the octet rule, which states that atoms tend to form bonds such that each atom has eight electrons in its valence shell.
### Molecule 1: H-C-O-H (Methanol)
- Carbon (C) has 4 valence electrons and forms 4 bonds (three with H and one with O).
- Oxygen (O) has 6 valence electrons and forms 2 bonds (one with C and one with H).
- Hydrogen (H) has 1 valence electron and forms 1 bond.
In methanol, each atom follows the octet rule:
- C: 4 bonds (8 electrons)
- O: 2 bonds + 4 lone pair electrons (8 electrons)
- H: 1 bond (2 electrons)
### Molecule 2: H-O-H (Water)
- Oxygen (O) has 6 valence electrons and forms 2 bonds (each with H).
- Hydrogen (H) has 1 valence electron and forms 1 bond.
In water, each atom follows the octet rule:
- O: 2 bonds + 4 lone pair electrons (8 electrons)
- H: 1 bond (2 electrons)
### Molecule 3: H-S-S-H (Disulfane)
- Sulfur (S) has 6 valence electrons and typically forms 2 bonds.
- Hydrogen (H) has 1 valence electron and forms 1 bond.
In disulfane, each atom follows the octet rule:
- S: 2 bonds + 4 lone pair electrons
- H: 1 bond (2 electrons)
### Molecule 4: H-B-B-H
- Boron (B) has 3 valence electrons and typically forms 3 bonds, however, it often does not fulfill the octet rule (8 electrons).
In H-B-B-H:
- Each B has 3 bonds (1 with H and 2 with B), totaling 6 electrons (falling short of the octet rule).
- H follows the duet rule with 1 bond (2 electrons).
The molecule H-B-B-H does not satisfy the octet rule for both boron atoms, making it unstable under normal conditions.
### Conclusion
The molecule H-B-B-H does NOT have the proper Lewis structure because the Boron atoms do not have enough electrons to satisfy the octet rule.
Therefore, the molecule that does NOT have the proper Lewis formula is:
4. H-B-B-H
